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author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-12-16 20:21:05 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-12-17 09:46:44 +0100 |
commit | 234da7bcdc7aaa935846534c3b726dbc79a9cdd5 (patch) | |
tree | a391afd465d6493a9f1bb274c225bab4d303aad0 /kernel/sched.c | |
parent | 416eb39556a03d1c7e52b0791e9052ccd71db241 (diff) | |
download | blackbird-op-linux-234da7bcdc7aaa935846534c3b726dbc79a9cdd5.tar.gz blackbird-op-linux-234da7bcdc7aaa935846534c3b726dbc79a9cdd5.zip |
sched: Teach might_sleep() about preemptible RCU
In practice, it is harmless to voluntarily sleep in a
rcu_read_lock() section if we are running under preempt rcu, but
it is illegal if we build a kernel running non-preemptable rcu.
Currently, might_sleep() doesn't notice sleepable operations
under rcu_read_lock() sections if we are running under
preemptable rcu because preempt_count() is left untouched after
rcu_read_lock() in this case. But we want developers who test
their changes under such config to notice the "sleeping while
atomic" issues.
So we add rcu_read_lock_nesting to prempt_count() in
might_sleep() checks.
[ v2: Handle rcu-tiny ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1260991265-8451-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index af7dfa74e6bb..7be88a7be047 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -9682,7 +9682,7 @@ void __init sched_init(void) #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP static inline int preempt_count_equals(int preempt_offset) { - int nested = preempt_count() & ~PREEMPT_ACTIVE; + int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); return (nested == PREEMPT_INATOMIC_BASE + preempt_offset); } |